package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.fasterxml.jackson.annotation.JsonAlias;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.boot.autoconfigure.cache.CacheProperties;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.SHOP_GEO_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private CacheClient cacheClient;
    @Override
    public Result queryById(Long id) {
        // 缓存穿透
///        Shop shop1 = cacheClient.
///                queryWithPassThrough(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //互斥锁解决缓存击穿
        Shop shop = queryWithMutex(id);
        //设置逻辑过期时间解决缓存击穿
//        Shop shop = cacheClient.
//                queryWithLogicalExpire(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        if (shop == null){
            return Result.fail("店铺不存在!");
        }
        return Result.ok(shop);
    }
    public Shop queryWithMutex(Long id) {
        //1.从Redis查询店铺缓存
        String key = RedisConstants.CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断缓存是否命中
        if (StrUtil.isNotBlank(shopJson)){
            //2.1命中,返回店铺信息
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        // 判断命中的是否是空值
        if (shopJson != null){
            return null;
        }
        //3.1未命中
        //3.2获取互斥锁
        String lockKey = RedisConstants.LOCK_SHOP_KEY;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey + id);
            //3.3判断是否获取成功
            if (!isLock){
                //获取失败,则休眠并重试
                Thread.sleep(50);
                return queryWithMutex(id);
            }
            //成功获取锁,进行二次查询redis缓存
            //1.从Redis查询店铺缓存
            shopJson = stringRedisTemplate.opsForValue().get(key);
            //2.判断缓存是否命中
            if (StrUtil.isNotBlank(shopJson)){
                //2.1命中,返回店铺信息
                Shop shopBean = JSONUtil.toBean(shopJson, Shop.class);
                return null;
            }
            //3.根据id查询数据库
            shop = getById(id);
            //4.店铺不存在,返回404
            if (shop == null){
                //将空值写入redis
                stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }
            //5.店铺存在,将店铺数据写入Redis
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            //6.释放锁
            unLock(lockKey);
        }
        //7.返回
        return shop;
    }
    public boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", RedisConstants.LOCK_SHOP_TTL, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);

    }
    public void unLock(String key){
        stringRedisTemplate.delete(key);
    }
//    public Shop queryWithPassThrough(Long id) {
//        //1.从Redis查询店铺缓存
//        String key = RedisConstants.CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断缓存是否命中
//        if (StrUtil.isNotBlank(shopJson)){
//            //2.1命中,返回店铺信息
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//        // 判断命中的是否是空值
//        if (shopJson != null){
//            return null;
//        }
//        //3.1未命中
//        //3.2根据id查询数据库
//        Shop shop = getById(id);
//        //3.1店铺不存在,返回404
//        if (shop == null){
//            //将空值写入redis
//            stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
//            return null;
//        }
//        //3.2店铺存在,将店铺数据写入Redis
//        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        return shop;
//    }
//    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
//    public Shop queryWithLogicalExpire(Long id) {
//        //1.从Redis查询店铺缓存
//        String key = RedisConstants.CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断缓存是否命中
//        if (StrUtil.isBlank(shopJson)){
//            //2.1未命中,返回空
//            return null;
//        }
//        //3.命中,需要先把Json反序列化成对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//        //4.判断缓存是否过期
//        if (LocalDateTime.now().isAfter(expireTime)){
//            //未过期,返回信息
//            return shop;
//        }
//        //过期,获取互斥锁
//        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
//        boolean isLock = tryLock(lockKey);
//        if (isLock){
//            //获取锁成功,二次检查缓存是否过期
//            if (LocalDateTime.now().isAfter(expireTime)){
//                //未过期,返回信息
//                return shop;
//            }
//            //5.利用线程池开启独立线程
//            CACHE_REBUILD_EXECUTOR.submit(() ->{
//                try {
//                    //6.重建缓存
//                    this.savaShop2Redis(id,1800L);
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                } finally {
//                    //7.释放互斥锁
//                    unLock(lockKey);
//                }
//            });
//        }
//        return shop;
//    }
//    public void savaShop2Redis(Long id, Long expireTimeSeconds){
//        Shop shop = getById(id);
//        //创建具有逻辑过期时间的对象
//        RedisData redisData = new RedisData();
//        redisData.setData(shop);
//        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireTimeSeconds));
//        stringRedisTemplate.opsForValue().set(RedisConstants.CACHE_SHOP_KEY,JSONUtil.toJsonStr(redisData));
//    }
    @Override
    @Transactional
    public Result updateShop(Shop shop) {
        Long shopId = shop.getId();
        //1.数据写入数据库
        if (shopId == null){
            return Result.fail("店铺id不能为空");
        }
        updateById(shop);
        //2.删除缓存
        String key = RedisConstants.CACHE_SHOP_KEY + shopId;
        stringRedisTemplate.delete(key);
        return Result.ok(shop);
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要根据坐标查询
        if (x == null || y == null){
            // 不需要坐标查询，接数据库查询
            Page<Shop> page = query()
                    .eq("type_id",typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            //返回数据
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //3.查询redis、按照距离排序、分页。结果：shopId、distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo() //GEOSEARCH BYLONLAT x y BYRADIUS 10 WITHDISTANCE
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );
        //4.解析出id
        if (results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        //4.1.截取from到end 的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String,Distance> distanceMap = new HashMap<>(list.size());
        if (from >= list.size()){
            return Result.ok(Collections.emptyList());
        }
        list.stream().skip(from).forEach(result -> {
            //4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //5.根据id查询Shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id, " + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //6.返回
        return Result.ok(shops);
    }
}
